Method and apparatus for jet propulsion through water



F. zwlcKY 3,044,253

.llull W, 1962 METHOD AND APPARATUS FOR JET PROPULSION THROUGH WATER 5Sheets-Sheet 1 Filed Feb. 4, 1947 INVENTOR. FRITZ Z W/CK Y July W, 11962zw 3,044,253

METHOD AND APPARATUS FOR JET PROPULSION THROUGH WATER 5 Sheets-Sheet 2Filed Feb". 4, 1947 INVENTOR.

1 7 FRITZ zw/c/rr AT TOR/V5 Y5 Jully W, 1962 F ZWICKY METHOD ANDAPPARATUS FOR JET PROPULSION THROUGH WATER Filed Feb. 4, 1947 ssheet-sheet 3 INVENTOR.

FRITZ ZW/C/(Y BY m ATTORNEYS July 17, 1962 F. ZWICK Y 3,044,253

METHOD AND APPARATUS FOR JET PROPULSION THROUGH WATER Filed Feb. 4, 19475 Sheets-Sheet 4 IN V EN TOR.

FRI 72 Z W/CK Y A T TORNEYS July 17, 1962 F. ZWICKY 3,044,253

METHOD AND APPARATUS FOR JET PROPULSION THROUGH WATER Filed F 1947 5Sheets-Sheet 5 V 96 98 3,61L #54752 42 6| 50 WATER FUEL) I 54 /05 93Jae/r PUMP 1 A, "1 Z 45 43 7 Ii '1 47 9/ I HUI I]! a W I] m ll l4 l5 I/E m g 3 g l r E 5 i t mzu. 1; mm TEMPERATURE A TTOl-P/VEYS United StatesPatent 3,044,253 METHOD AND APPARATUS FDR JET PROPULSTQN THRGUGI-I WATERFritz Zwicky, Pasadena, Qaliil, assignor, by mesne assignments, toAerojet-General Corporation, Cincinnati,

Ohio, a corporation of flhio Fiied Feb. 4, 1947, Ser. No. 726,334 20tilaims. (Cl. 60-355) This invention relates to jet propulsion, and moreparticularly to the jet propulsion of devices through a water medium.

The principal object of the invention is to provide a method and meansof operating a jet propelled device through water with high efliciencyand impulse and without excessive overheating.

In my co-pending application Serial Number 661,485, filed April 12,1946, now abandoned, I have disclosed and claimed the reaction of lightmetals with water for the purpose of producing high specific impulsejets for developing thrust. The use of such propellants for producingthrust has the desirable features that it does not involve detonable,corrosive, or toxic materials. Furthermore, no ignition device isrequired and excessively high reaction chamber temperatures are avoided.A further advantage of the use of such propellants is that they possesshigh density impulse. By density impulse I mean the product of theaverage specific gravity of the substance multiplied by the specificimpulse.

My present invention is based upon my discovery that the speed ofreaction between water and the light metals or light metal compounds oralloys can be increased by first melting the light metal substance andthen subjecting the molten material to a degree of heating above itsmelting point before bringing it into contact with the water.

I have found, furthermore, that these metals are characterized by a verymarked increase in the rate of spontaneous reaction at a critical degreeof heating above the melting point. The phenomenon is quite marked, as Ihave found that by increasing the temperature of these light metals upto the melting point, there will usually be only a slight increase intheir rate of reaction with the water. But upon increasing thetemperature somewhat further, up to the critical temperature somewhatabove the melting point, the reaction rate suddenly increases to themuch greater rate.

I make use of the light metal propellant materials for jet propulsionthrough a water medium by the provision of means for superheating thelight metal or light metal compounds or alloy propellant to the desiredtemperature above its melting point; and then bringing this superheatedpropellant material into contact with the water of the medium within thedevice to produce spontaneous reaction or decomposition.

A motor or unit suitable for the purpose may comprise a fluid channel orduct having an inlet opening and an exhaust opening or nozzle and areaction chamber or region within the duct between the inlet and outletends. A suitable valve placed between the inlet opening and the reactionchamber will serve to admit the water and to enable the pressure to bebuilt up in the reaction chamber.

A feature of my invention is the provision of an auxiliary reactionchamber in correlation with the main reaction chamber, the auxiliarychamber being provided with means for heating the propellant materialand discharging it at a proper rate into the main reaction chamber.

A related feature is the provision of means associated with theauxiliary reaction chamber for initially heating the propellant materialbefore allowing it to be injected into the main reaction chamber for thespontaneous reaction with the water.

Patented July 1'7, 1962 The foregoing and other features of my inventionwill be better understood from the following detailed description andthe accompanying drawings of which:

FIG. 1 is a longitudinal plan view showing the assembled motor:

FIG. 2 is a front elevation of the motor of FIG. 1;

FIG. 3 is an enlarged cross section view showing the injector assemblyand auxiliary reaction chamber;

FIG. 4 is a cross section on the line 4-4 of FIG. 3 showing the lowerportion of the injector and the auxiliary heating chamber rotated fromthe view shown in FIG. 3 and showing the main injection orifices.

PEG. 5 is an end plan view of the auxiliary reaction chamber showing theauxiliary jet orifices with the auxiliary nozzle removed;

FIG. 6 is a perspective view of one of the valve blades;

FIG. 7 is a broken perspective view taken from above showing the mannerin which the valve blades cover the channels;

FIG. 8 is an end plan view partly in cross section showing a valve bladeinterleaved between two valve channels;

FIG. 9 is a cross section view of the valve assembly taken on the line9-9 of FIG. 1;

FIG. 10 is a diagrammatic view of the assembled motor; and

FIG. 11 is a graphical representation of the effect of temperature onthe reaction rate of propellant materials.

The jet motor shown in the drawings comprises a duct 10 having an inletopening or mouth 9 and an exhaust opening or nozzle 15. Within the inletopening there is located a valve assembly 12; and between the valve andthe exhaust opening there is a reaction chamber 11.

The reaction chamber 11 begins at the rear of a valve assembly 12 andits forward end conforms with the out line of valve housing 12a which inthis case is rectangular. The reaction chamber 11 then undergoes atransition from the rectangular to a circular shape as it progressesdownstream. The rear end of the reaction chamber is provided with acoupling member 14 to which is attached the exhaust nozzle 15. Anopening 16 is provided in a wall of the reaction chamber 11 whichpermits insertion of an injector or auxiliary reaction chamber unit 13.

The auxiliary reaction chamber unit 13 comprises a body member 20 whichhouses a pintle controlled flow regulator and an auxiliary reactionchamber 18. The portion of body member 20 which houses the flowregulator is outside the reaction chamber 11, and the portion whichhouses the auxiliary reaction chamber is located inside the reactionchamber 11. An auxiliary jet orifice 19 is attached to auxiliaryreaction chamber 18.

The injector and auxiliary reaction chamber member is constructed asfollows: The portion of the body member 20 which extends outside thereaction chamber is preferably cylindrical in shape and is madesubstantially larger in diameter than the opening 16 which is made inthe walls of the reaction chamber 11. The diameter of that portion ofthe cylindrical body member 20 which is placed inside the reactionchamber is reduced so that it fits within the opening 16 in the reactionchamber wall. A reduction in diameter forms an annular shoulder 21 whichrests against a boss 22, which is attached securely around the opening16. The diameter of the portion of body member 20 which is inside thereaction chamber is continued at the reduced diameter up to end 23. Aspiral groove 24 is provided in the outer surface of reduced portion ofbody member 20 starting at a point located a substantial ditsance belowshoulder 21 and continuing to within a short distance of end 23. Thisforms a spiral partition 25 which has the same outer diameter as thereduced portion of cylindrical body 20. A radial hole 40, perpendicularto the axis of the body 20 is drilled from the top uppermost channel toa point slightly beyond the center of body 20.

An axial hole 28 is provided in the reduced portion of body member 20starting at end 23 and continuing to a point approaching approximatelythe start of the second turn of the spiral groove 24. A series of fins29 starts 'from the circumference of hole 28 and continues to within ashort distance of the inner wall of the spiral conduit 24. Fins 29extend from the upper end of axial hole 28 and continue to within ashort distance of end 23 of the body member 20. These fins arepreferably uniformly spaced over the entire circumference of hole 28 asshown in FIGS. 4 and 5. The area formed by the axial hole 28 includingthe space between fins 29 constitutes the auxiliary reaction chamber 18.

The diameter of axial hole 28 is increased for a short distance from end23 until it conforms with the largest diameter of the circle for-med bythe bottom of the fins 29. Threads 30 are provided on this increaseddiameter.

1 An annular sleeve 26 is provided to slide snugly over the outercircumference of spiral partition 25. The outer diameter of sleeve 26corresponds to the diameter of opening 16 and the opening in boss 22 andits inner diameter is proportioned to fit snugly over the end of thespiral partitions 25. Sleeve 26 extends from the annular shoulder 21 tothe lower end 23 of body member 20 and when in this position closesspiral groove 24 to form a spiral channel. Leakage from the spiralchannel past the ends of sleeve 26 is prevented by providing a pair ofannular grooves 31 and 32 located just above and below the ends ofspiral groove 24. rings 33 and 34 are seated inside of annular grooves31 aind 32 making the sleeve leakproof. That portion of sleeve 26, whichcorresponds to the last three turns of spiral groove 24, is providedwith 'a plurality of orifices 35 positioned so as to be centered withrespect to the upper and lower walls of the channel which they face, andare located at uniform intervals around the circumference of the sleeve.These orifices are drilled at varying angles with respect to the bodymember 20* to permit injections of streams of liquid at varying angles,for example, the upper groove orifices would form an angle less than 90,with the central axis, pointing toward the top of the reaction chamher,the central ones would be perpendicular to the central axis of the body20 and the lower ones would form an angle greater than 90 with thecentral axis of body member 20 as has been indicated in FIG. 4.

A cup-shaped member 17 provided with threads to engage threads 30 andhaving substantially the same outside diameter as that of sleeve 26 isthreaded on until it presses against sleeve 26 and the lower end 23 ofthe reduced portion of body member 20. The cup-shaped member 17 isprovided with a nozzle 19 preferably of the De Laval type, which whenthe unit is installed in the jet motor has its axis pointing toward theexhaust end of the duct 15. The gases fromthe reaction chamber 18collect in cup-shaped recess 17 and then escape through nozzle 19 intothe main reaction chamber 11.

' The portion of body member 20 which is outside of the reaction chamberis provided with an axial bore 36 which extends into the cylindricalbody a substantial distance from end 3-7. The diameter of bore 36 isthen reduced and continued at a lesser diameter to within a shortdistance of the upper edge of radial hole 40 forming a cylindrical space38. At this point the diameter of the bore is greatly reduced to form aconnecting channel 39 which opens into conduit 40, thus connecting thecylindrical area 38 with the uppermost turn'of spiral groove 24.

An orifice 41, smaller in diameter than connecting channel 38, isdrilled on the axis of the body member 20 and connects the upper end ofauxiliary reaction chamber 18 with radial hole 40.

Bore 36 is provided with an annular recess 42 which is positioned asubstantial distance from the end '37 of 4 body member 20. The portionof bore 36 above annular recess 42 is counter bored to a slightly largerdiameter 36a.

A threaded bore 43 is provided which is preferably perpendicular to theaxis of body member 20 and is positioned so that it can be connected toannular recess 42 by a smaller channel 44.

A second threaded bore 45, also perpendicular to the axis of body member20 and preferably in the same longitudinal plane passing through theaxis of threaded bore 43 is provided in the cylindrical body 20 belowbore 43. Bore 45 is positioned so that a short conduit 46', smaller indiameter than bore 45, will connect it with the lower end of bore 36. vA third threaded bore 47 drilled on the same longi tudinal plane asbores 43 and 45 and positioned below bore 45 is provided near the lowerend of the enlarged portion of body member 20. This bore is connected tothe reduced bore 38 by means of a connecting channel 48.

A fourth threaded bore 49, preferably located on the same longitudinalplane as bores 43, '45 and 47 is positioned near the upper end 37 ofcylindrical body 20 and is connected 'to the upper end of thecylindrical space formed by axial bore 36a by a connecting passage 50.

A hole 51 perpendicular to the axis of body member 20 is preferablylocated on the same longitudinal plane as that described by the axis ofholes 43, 45, 47 and 49 but placed on the opposite side of the axis ofcylindrical body 20 from bores 43, 45, 47 and 49. Hole 51 is continueduntil it intersects central bore 36. The upper end of this bore ispositioned so that it will intersect bore 36 a short distance below thelower edge of annular recess 42.

A hole 52 lying in substantially the same longitudinal plane asdescribed by the axis of bores 43, 45, 47 and 49, but on the same sideas transverse hole 51 is drilled from the upper end 37 of cylindricalbody 20 and is continued to within a short distance {of upper end ofauxiliary reaction chamber 18. This hole connects to the .upper end ofthe auxiliary reaction chamber 18 by means of an orifice 53 of smallerdiameter drilled from the side of the reduced portion of body member 20at an angle such that it will intersect the axis of orifice 41 at apoint within reaction chamber 18.

Bore 52 is shown in the illustration FIG. 3 to be drilled at an angle tothe axis of cylindrical body 20. This is done to permit orifice 53 to bepositioned more suitably with respect to orifice 41. The outer end ofbore 51 and the upper end of bore 52 are then plugged to, preventleakage. This may be done either by a threaded plug, welding, or othersuitable means. The flow of liquid from bore 47 into the lower portionof bore 38 is regulated by a pintle 54. Pintle 54 comprises apiston-shaped portion 55, which conforms with the diameter of bore 36, abearing section 56 which is smaller in diameter than piston-shapedportion 55 and corresponds with the diameter of bore 38, and a closureportion 57 which is smaller in diameter than bearing por tion 56. Theend of closure section 57 is ground to form a conical tip 58 which seatsin the small connectinglbore 39. The lower portion of bearing section 56is provided with an annular groove 59 inwhich is seated an O ring 69.This 0 ring prevents the passage of any fluid from the lower region ofbore 38. V

The flow of liquid from bore 43 and annulus 42 into the cross channel 51and through orifice 53 is controlled by a closure member 61 whichisnormally seated against the head of piston portion55 of pintle 54.This closure member is proportioned to snugly fit into bore 36 andcounter bore 36a and is constructed asfollows: Starting at the upper endwhich, when the pintle isiin its closed position, will extend asubstantial distance above the upper end of annulus 42 and continuing tothe bottom edge of annulus 42, the diameter of section 62 of the closuremember conforms with the diameter of counterbore 36a forming the largerupper bearing surface. The lower end of closure member s1 which comes incontact with the head of piston member 55 is proportioned to conformwith the diameter of bore 36 and forms lower bearing surface 63. Thediameter of the closure member is reduced between the bearing surfacesto form an annular channel 64 when the closure member is inserted intobores 36 and 36a.

Since the diameter of counterbore 36a is greater than the diameter ofbore 36 the diameter of the bottom surface of upper cylindrical bearingsection 62 will be a little greater than the diameter of bore 36 thusforming a narrow annular contact surface 65. This surface may be groundto form a valve seat which will help prevent the flow of liquid intoannular channel 64 when the pintle is in its closed position.

The upper bearing surface 62 is provided with a groove 66 positioned tobe at all times above annulus 4-2. An ring 67 is inserted in thisannular groove and prevents the liquid from flowing past annulus 42 intothe upper portion or" counter bore 360 above the closure member 61. Thelower bearing surface 63 is likewise provided wtih a groove 68 and an Oring 69 which prevents the flow of any liquid from either bore 45 orannular channel 64.

The upper end of cylindrical body 20 is closed by a cap 70 whichpreferably has a recessed portion 71, conforming with counterbore 36a.Cap 79 is provided wtih an annular groove 72 positioned a short distancefrom recessed portion 71 and in which may be seated a gasket 71%.

The construction of the valve assembly 12 employed in this apparatus isdescribed in detail with reference to FIGS. 2, 6, 7, 8 and 9. The valveis the flutter or blade valve type; and is built up of an assembly ofalternating flexible blades 75 and rigid channel members 76. Each of thechannel members 76 comprises a rectangular plate 77, the upper surfaceof which is provided with a number of partitions 78 which are integralwith plate 77 and run parallel to each other as shown. These partitionsform a series of channels 79 which taper in depth being deeper at theleading edge 8t} and tapering at the rear edge 81 to coincide wtih thethickness of the rear edge of the blade 75 in assemblying the valve unit12, several flexible blades 75 are alternately interleaved between theseveral channel members 76 and are firmly held near the leading edges 82between the channel plate 77 of one channel member and the upper edge 99of partitions 78 of the next channel member. These valves and rigidchannel members are securely held together in a valve housing 193 bybolts 84 which pass through holes 85' provided in botn the flexibleblades 75 and rigid channel members 7 as shown in FIG. 9. The centralportion of the valve assembly is held in compression by a series ofcompression bolts 86 which press against a bearing plate 87. Valvehousing 83 is shown as rectangular for convenience only but any othersuitable shape may be employed. When a series of these valves andchannel members are installed in the valve housing to form a completedvalve assembly 12 they completely fill the space just preceding thereaction space 11. For purpose of assembly the completed valve slidesinto the valve housing 83 and is held in position by bolts 84,compression bolts 86 and shoulder shaped retainers 38 which are boltedto the forward portion of the sides of the valve channel 10.

FIGS. 7 and 8 are views illustrating the manner in which one of theblades is sandwiched between two of the channel members and FIG. 7 showa cutaway view looking into the channel member 76 showing its relationto a valve blade 75. The arrangement is such that the lower sides 39 ofall flexible blades are enabled to vibrate so as to alternately contactand move away from the top edge 99 of partition members 78. This createsthe valve action placing the valve in closed position when the blades 75are against the top of partition member 78 and permitting the flow ofliquid when the pressure against the valves from the forward side issufficient to raise the rear portion of the valve leaf away from the topof channel partition member 78.

The operation of the unit will be better understood with reference toFIG. 10 which is a schematic drawing and FIG. 3 showing the manner inwhich the apparatus operates, A compressible gas, such as nitrogen,oxygen, air or other gas is introduced under pressure from tank 98 intothe upper portion of bore 36a above the head of closure member 61through threaded bore 49 and connecting passage 50, the pressure beingmaintained constant by any suitable regulating means such as a reducingvalve 91.

A liquid such as oil is supplied to threaded bore 45 by a jerk pump 92,driven by a motor M, or any other suitable device Which canintermittently place the liquid under pressure. The use of a jerk pumpto operate a pintle intermittently is described in the copendingapplicational Serial No. 652,430, filed March 6, 1946 entitled Injector.One outlet conduit from the jerk pump is connected to threaded hole 45by a conduit 93 thus supplying liquid under pressure from pump 92,through connecting hole 46 and to the lower end of axial bore 36. Thisliquid under pressure acts against the bottom of piston-shaped member55' causing it to raise Whenever the pressure against the bottom exceedsthe pressure exerted by the gas cushion in the upper portion of bore 36awhich is transmitted by closure member 61. Whenever the pressure exceedsthat of the gas the pintle 54 moves upwards thus opening a continuouspassage between annular channel 64 and annular groove 42, at the sametime raising the closure tip 53 from the channel 39. One reactingliquid, water in this example, flows under pressure from its storagetank 94 through conduit 95, then into threaded bore 43, connectingpassage 44 and into annular groove 42. The other reacting liquid underpressure is supplied from storage tank 96 through conduit 97, into bore47, connecting conduit 98 into the lower annular space of bore 38 formedwhen the reduced diameter 57 of the pintle 54 is in position in bore 38.When the pressure against the bottom of piston member 55 is sufficientto raise pintle 54 and closure member 57 the liquid in the lower portionof the bore 38 will flow through orifice 39 into connecting channel 4i)and through a spiral channel 24 surrounding auxiliary reaction chamber18, permitting the liquid to exit through orifices 35 provided in sleeve26. A small portion of the liquid flowing through orifice 39 will alsoescape through orifice 41 into the auxiliary reaction chamber 18.

When the pintle and closure member are raised the annular space M willbe facing both the annular groove 42 and transverse conduit 51 thuspermitting liquid coming through connecting hole 44 to fiow from annularchannel 42 into conduit 51, connecting channel 52 and through orifice'53. This liquid escaping through orifice 53 will impinge against thestream escaping through orifice 41, thus permitting the materials toreact within the auxiliary reaction chamber 13. A suitable heatingdevice 1495 will be required to keep the fuel in container as in amolten state and heated to the proper degree. Tank 94 is pressurized bygas in tank 98 and the pres sure is controlled by a regulating valve 99.Likewise tank 96 is pressurized by tank 94 and the pressure iscontrolled by a regulating valve tea.

The water reactive liquid passing through the spiral channel 24 willabsorb heat that is produced by the reaction between the spontaneouslyreactive liquids coming in contact from orifices 41 and 53 thus heatingthe main body of fuel and accelerating the rate of reaction between thewater reactive material and the water in the reaction chamber 11. Theconducting fins 29 assist in transferring a large portion of the heatdeveloped by the reaction within the auxiliary chamber 18 to the sidesof the spiral channel 24.

Since the device is submerged in water the entire reaction chamber 11will be filled with liquid. The intermittent injection of the lightmetal propellant substance into the water at an intermittent rateproduces intermitent reactions which intermittently raise the pressurein the chamber. At each intermittent increase of pressure the valvemechanism will close thereby forcing the reaction product along with thewater out the entrance nozzle to produce the reaction thrust. Betweenthese reactions in the chamber the valve will open to allow the water toenter, thereby providing the desired fiow of water through the duct.

Thus when the water reactive liquid escapes through the orifices 35 itwill come immediately in contact with the water and spontaneously reactwith it. Whenever the pressure Within the main reaction chamber 11 dropsbelow the pressure of the Water bearing against the incoming end ofvalve assembly 12 the valve blades 75 will open permitting scavengingand introducing a fresh charge of Water into the reaction chamber 11 andconduit 10.

The products of reaction from auxiliary reaction cham-' ber 18 escapethrough the auxiliary nozzle throat 19. By suitably proportioning thesize of the nozzle H of the auxiliary jet motor it is possible tomaintain a relatively high pressure within the auxiliary reactionchamber 18 at all times producing a substantially continuous dischargethrough the nozzle. This has the effect of smoothing out the lowpressure periods between pulses which occur during the intervals whenall injection orifices are closed.

- I prefer to use a propellant selected from a metal, metal hydride ororgano-metallic compound which, at their critical temperatures, arereactive with water. However, I have found that those electropositivemetals found in the electromotive series of the elements havingelectrode potentials of at least 0.7 volt and including all of themetals-having electrode potentials above this value, their hydrides, theorgano-metallic compounds of these metals or their alloys, such as, forexample sodium potassium alloy and an alloy of aluminum and magnesiumcalled magnalium are the most effective propellants. Examples of themetals included in this group are lithium, beryllium, boron, sodium,magnesium, aluminum, silicon, potassium, calcium, scandium, titanium,rubidium, barium, manganese, tellurium and zinc. Thus, I may employ as apropellant a molten stream of sodium, lithium, or the like, a heatedliquid stream of lithium hydride, sodium hydride, boron hydride,aluminum borohydride or the like, or a heated liquid stream of aluminumethyl hydride, triethylboron, sodium methylate or the like.

The most desirable amount of heat above the melting point will vary withthe different materials. For example, metallic sodium has a meltingpoint of 97.5 C. and if heated to 110 C. will explode on contact withwater, a differential of 12 /2 C., while potassium has a melting pointof 623 C. and explodes in water at 69 C., a differential of only 6.7 C.On the other hand sodium potassium alloy K Na has a melting point ofabout 1 C. but will not explode in water until the temperature has beenraised to 76 C., a differential of 77 C.

FIG. 11 shows graphically the effect of temperature upon the reactionrate of the metallic materials suitable for fuel which have been listedabove. The curve shows a small increase in the reaction rate in therange between ambient temperatures and the melting point of thematerial. The substances exhibit a slightly greater increase in thereaction rate in the temperature range between the melting point of thematerial and its critical temperature above the melting point (1critical). At t critical the reaction rate rises rapidly assuming almosta vertical slope until the material approaches its maximum reaction ratewhich is illustrated by the solid line in the curve. The term criticaltemperature as used in the specification and claims means thattemperature above the melting point at which the reaction rate makesthis sudden rapid rise. eyond the point at which maximum reaction rateis reached excess heatin appears to have no additional beneficialeifect. The dotted curve shows the path which the curve would beexpected to follow if the above phenomena did not take place.

The advantages that are derived from operating the apparatus and processin the manner described above are as follows: Since the t critical isconsiderably lower in temperature than the temperature which would berequired to reach an equivalent reaction rate (shown by the dotted line)if the above phenomena did not occur, the thermodynamic eificiency ofthe reaction cycle, that is, generation of hot H and the expansion of Hwith the accompanying scavenging stroke increases and causes:

(1) A high peak pressure p accompanied with a correspondingly highexpansion ratio from the peak pressure to the exit pressure or the freestream pressure.

(2) The expansion from the high pressure p takes place so rapidly thatthe heat losses from the hot gases to the surrounding fluid areappreciably reduced.

(3) By increasing the diiferential between peak pressure and the exhaustpressure the degree of under pressure or suction obtained at the end ofa work cycle from the system increases.

The low value of minimum pressure and the resulting suction possessesthe advantage that the amount of thrust obtained during the scavengingstroke is increased and the cycling frequency can also be increased sothat a higher cross section of specific thrust is obtained. This isdefined as the total average thrust divided by the cross section of theduct.

Other variations and modifications will occur to those skilled in theart without departing from the spirit or scope of the foregoingdescription.

I claim:

1. In the operation through water of a reaction propelled device of thetype having a duct provided with an inlet opening through which water isadmitted, an exhaust nozzle through which water is ejected, a valvelocated in the duct and a reaction chamber between the valve and exhaustnozzle, the improvement which comprises heating a metallic waterreactive propellant to cause it to melt, adding sufficient heat to heatthe molten mass at least to the critical temperature above the meltingpoint, injecting the molten material at a temperature at least as greatas the critical temperature into the reaction chamber, and contactingthe hot propellant liquid with the water within the reaction chamberthereby creating a violent reaction which creates pressure which closessaid valve and creates an exhaust jet through the exhaust nozzle.

2. The improvement according to claim- 1 in which the water reactivepropellant is a substance selected from the group consisting ofelectropositive metals in the elec tromotive series of the elementshaving electrode potentials of 0.7 volt or greater, alloys of thesemetals, and their organo-metallic hydrides.

3. The improvement according to claim 1 in which the water reactivesubstance is sodium.

4. The improvement according to claim 1 in which the water reactivesubstance is potassium.

5. The improvement according to claim 1 in which the water reactivesubstance is magnesium. 6. The improvement according to claim 1 in whichthe water reactive substance is lithium.

7. The improvement according to claim 1 in which the water reactivepropellant is sodium potassium alloy.

8. The improvement according to claim 1 in which the water reactivepropellant is aluminum borohydride.

9. The improvement according to claim 1 in which the water reactivepropellant is ethyl aluminum hydride.

10. A reaction propelled device adapted for propulsion through a watermedium, comprising a passageway having an inlet opening for permittingentry of water from the surrounding medium, an exhaust nozzle throughwhich the water is ejected, an automatically operable valve located insaid passageway, said valve being ope-rable to open to admit fluid fromthe medium when the pressure on the inlet side of the valve is greaterthan the pressure on the outlet side of the valve and closing the saidvalve when the pressure on the outlet side is greater than the pressureon the inlet side, a main reaction chamber between the valve and thenozzle, an auxiliary reaction chamber Within said reaction chamber, saidauxiliary reaction chamber being provided with a nozzle discharging intosaid reaction chamber, means for injecting intermittently into saidauxiliary reaction chamber a stream of water and simultaneouslyinjecting into said auxiliary reaction chamber a stream of propellant,means for injecting intermittently into the main reaction chamber awater reactive propellant, heat transfer means for conducting the heatdeveloped by the reaction in the auxiliary reaction chamber to the mainwater reactive propellant thereby heating it to a predetermined degreebefore it is injected into the water in the main reaction chamber andthereby causing its decomposition in developing intermittent pressureattended by the ejection of the products of reaction and water throughthe exhaust nozzle.

11. A reaction propelled device according to claim in which the nozzleattached to the auxiliary reaction chamber is proportioned to maintainat all times the positive pressure within said auxiliary reactionchamber.

12. A jet motor comprising a passageway for the entry of Water from themedium surrounding said jet motor, an exhaust nozzle through which saidWater is ejected, means for introducing a metallic substancespontaneously reac tive with said water at a point intermediate betweensaid passageway and said exhaust nozzle, means in association with saidlast named means for heating said substance to its critical temperature,and means in association with said passageway for stopping the entry ofsaid fluid when the pressure at said intermediate point is greater thanthe pressure on the inlet side of said passageway.

13. A jet motor comprising a passageway for the entry of Water from themedium surrounding said jet motor, an exhaust nozzle through which saidwater is ejected, a main reaction chamber intermediate between saidexhaust nozzle and said passageway, conduit means for introducing intosaid main reaction chamber a substance spontaneously reactive with saidwater, an auxiliary reaction chamber within said main reaction chamberin heat exchanging relationship with said conduit means and wherein aportion of said substance is caused to react spontaneously with water toadd heat to said substance introduced into said main reaction chamber.

14. A jet motor according to claim 13 wherein said passageway isprovided with means for controlling the flow of said fluid therein, saidmeans comprising a flutter valve whereby the flow of fluid from saidmedium into said main reaction chamber is stopped when the pressurewithin said main reaction chamber exceeds the pressure exerted at theinlet point of said passageway.

15. A jet motor for operation through a fluid, comprising a primaryreaction chamber, a passageway leading from the exterior of said motorinto said primary reaction chamber, an exhaust nozzle in associationwith said reaction chamber and communicating with the exterior of saidmotor, a pressure responsive valve disposed within said passageway topermit the flow of fluid in which said motor is suspended only in thedirection of said primary reaction chamber, an auxiliary reactionchamber within said primary reaction chamber, means for introducing asubstance spontaneously reactive with said fluid into said auxiliaryreaction chamber, means for introducing a quantity of said fluid, thesame as said first-mentioned fluid, into auxiilary reaction chamber,means within said auxiliary reacting chamber for causing a portion ofsaid substance to react with said fluid and for preventing the remainingportion of said substance from reacting with said'fluid whereby saidremaining portion of said substance is heated, and means for introducingsaid remaining portion of said substance to said primary reactionchamber.

16. In the operation through water of a reaction propelled device of thetype having a duct provided with an inlet opening through which water isadmitted, an exhaust nozzle through which water is ejected, a valvelocated in the duct and a reaction chamber between the valve and theexhaust nozzle, the improvement which comprises intermittently injectinginto the water in the reaction chamber a molten metallic water reactivepropellant at a temperature which is at least as high as the criticaltemperature above the melting point at which the rate of reactionwithwater rapidly increases, thereby producing intermittent reactions withgreat violence and creating pressures which close the valveintermittently thereby creating an exhaust jet through the exhaustnozzle.

17. The improvement according to claim 1 in which the water-reactivepropellant is a substance selected from the group consisting of sodiumpotassium alloy, magnalium, lithium, beryllium, boron, sodium,magnesium, aluminum, silicon, potassium, calcium, scandium, titanium,rubidium, barium, manganese, tellurium, zinc, lithium hydride, sodiumhydride, boron hydride, aluminum borohydride, aluminum ethyl hydride,triethylboron, and sodium methylate.

18. The improvement according to claim 1 in which the Water reactivesubstance is boron.

19. The improvement according to claim 1 in which the water reactivesubstance is silicon.

20. An injector for injecting molten fuel into a combustion chamber,comprising a spiral conduit adapted to be inserted within the chamber, aplurality of orifices through the spiral conduit to allow liquid to beinjected from the spiral conduit into the chamber, a combustion regionwithin the spiral conduit and means for injecting Water and also some ofsaid liquid propellant into said combustion region to produce a reactionwhich will create heat to heat up the liquid travelling through thespiral conduit.

References Cited in the file of this patent UNITED STATES PATENTS515,500 Nobel Feb. 27, 1894 870,308 McGonigle Nov. 5, 1907 1,656,486Huntington et a1. Jan. 17, 1928 FOREIGN PATENTS 491,331 France Jan. 30,1919 857,780 France Apr. 26, 1940 863,928 France Jan. 6, 1941 425,604Great Britain Mar. 13, 1935

